197143-13-8Relevant articles and documents
Concise Total Synthesis of (?)-Affinisine Oxindole, (+)-Isoalstonisine, (+)-Alstofoline, (?)-Macrogentine, (+)-Na-Demethylalstonisine, (?)-Alstonoxine A, and (+)-Alstonisine
Stephen, Michael Rajesh,Rahman, M. Toufiqur,Tiruveedhula, V. V. N. Phani Babu,Fonseca, German O.,Deschamps, Jeffrey R.,Cook, James M.
, p. 15805 - 15819 (2017)
A highly enantio- and diastereoselective strategy to access any member of the sarpagine/macroline family of oxindole alkaloids via internal asymmetric induction was developed from readily available d-(+)-tryptophan. At the center of this approach was the diastereospecific generation of the spiro[pyrrolidine-3,3′-oxindole] moiety at an early stage via a tert-butyl hypochlorite-promoted oxidative rearrangement of a chiral tetrahydro-β-carboline derivative. This key branching point determined the spatial configuration at the C-7 spiro center to be entirely 7R or 7S. Other key stereospecific processes were the asymmetric Pictet–Spengler reaction and Dieckmann cyclization, which were scalable to the 600 and 150 gram levels, respectively. Execution of this approach resulted in first enantiospecific total synthesis of (+)-isoalstonisine and (?)-macrogentine from the chitosenine series (7R), as well as (+)-alstonisine, (+)-alstofoline, (?)-alstonoxine A and (+)-Na-demethylalstonisine from the alstonisine series (7S).
Enantiospecific Total Synthesis of the Sarpagine Related Indole Alkaloids Talpinine and Talcarpine as Well as the Improved Total Synthesis of Alstonerine and Anhydromacrosalhine-methine via the Asymmetric Pictet-Spengler Reaction
Yu, Peng,Wang, Tao,Li, Jin,Cook, James M.
, p. 3173 - 3191 (2007/10/03)
The enantiospecific total synthesis of talpinine 1 and talcarpine 2 has been accomplished from D-(+)-tryptophan in 13 steps (11 reaction vessels) in 10% and 9.5% overall yields, respectively. Moreover, this synthetic approach has been employed for the improved synthesis of alstonerine 3 and anhydromacrosalhine-methine 4 in 12% and 14% overall yield, respectively. A convenient synthetic route for the enantiospecific, stereospecific preparation of the key intermediate (-)-Na-H, Nb-benzyl tetracyclic ketone 15a via the asymmetric Pictet-Spengler reaction on a multihundredgram scale has been developed. A diastereocontrolled (>30:1) anionic oxy-Cope rearrangement and the intramolecular rearrangement to form ring-E and an Nb-benzyl/Nb-methyl transfer reaction also served as key steps. This general approach can now be utilized for the synthesis of macroline/ sarpagine related indole alkaloids and their antipodes for biological screening.
The enantiospecific total synthesis of norsuaveoline
Wang, Tao,Yu, Peng,Li, Jin,Cook, James M.
, p. 8009 - 8012 (2007/10/03)
Norsuaveoline la has been synthesized enantiospecifically in 28% overall yield from commercially available D-(+)-tryptophan methyl ester via the asymmetric Pictet-Spengler reaction and a stereocontrolled oxy-anion Cope rearrangement as key steps.
